greybus: firmware: s/_LEN/_SIZE

Alex Elder pointed out that the macros also count the trailing NULL
('\0') character and so it should be using SIZE instead of LEN.

This patch makes that change.

Reported-by: Alex Elder <alex.elder@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: firmware: Fix typo in documentation

s/shall be used the user/shall be used by the user/

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: firmware: Update Documentation and sample application

Update documentation and sample application to capture the 'status' byte
in backend version operation and new error types in backend firmware
update operation.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: Documentation: Document Authentication interfaces

This patch defined userspace interface of the CAP protocol.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jun Li <li_jun@projectara.com>
Tested-by: Jun Li <li_jun@projectara.com>
Signed-off-by: Alex Elder <elder@linaro.org>

greybus: firmware: prefix char-device with 'gb-'

This will make it consistent with any other character devices we have
for greybus and let us identify greybus character devices easily.

Compiled tested only.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: firmware: Fix spelling mistake

s/directly/directory :)

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: Documentation: Document firmware-management interfaces

This patch adds a new 'firmware' folder in Documentation, which contains
two files:

- firmware-management: This describes the userspace interface for
interacting with firmware-management bundle.

- firmware.c: Sample application to test firmware load for Interface
Firmware and firmware updates to Backend Interface Firmware.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jun Li <li_jun@projectara.com>
Tested-by: Karthik Ravi Shankar <karthikrs@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>